image sprite is packed very asymmetrically - triggers poor rendering performance in firefox3 and missing icons in firefox4 and konquerer
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Launchpad itself |
Triaged
|
High
|
Unassigned | ||
Mozilla Firefox |
Unknown
|
High
|
Bug Description
Ubuntu 10.10. Viewing a bug, e.g.
https:/
slow in Firefox. It's observable in many ways, e.g. scrolling is
extremely sluggish, especially when the top of the page is neared. Even
having the page redraw on an X Expose event takes seconds, e.g. when
Firefox is unminimised with the bug tab selected. The CPU fan audibly
steps. The X server continues to process other clients though during
Firefox's hiatus.
If I adblock just
https:/
speed is restored. This is a PNG although the HTTP server is specifying
a text/plain content-type.
$ HEAD https:/
Content-Type: text/plain
$ wget -qO- https:/
/dev/stdin: PNG image, 64 x 20553, 8-bit/color RGBA, non-interlaced
It is of huge vertical size. A friend reports Webkit also having issues
with the Bug View page using it, but not Opera. Perhaps Firefox and
Webkit hand the huge image onto the X server but Opera cuts out the
sprites itself and hands many small images on. I'm using Nvidia
graphics hardware and did find this comment by an AaronP, an Nvidia
employee.
http://
Re: launchpad.net bug views excruciatingly slow
Thanks for reporting this. I took a look today, and it appears that
Firefox is using an enormous pixmap that exceeds the GPU's maximum
rendering dimensions, causing software fallbacks. While we will
attempt to make it as fast as possible, performance would be greatly
improved if Firefox would render using surfaces that fit within the
maximum renderable dimensions.
A brief look at .../rev12670/
so poorly giving such a large height. The simplest solution may be to
pack the sprites more tightly resulting in a dense squarish image. I
agree with AaronP that perhaps Firefox could cope better but it seems
poor for Launchpad to dish up such a sprite collection.
As it stands, viewing bugs on Launchpad is very frustrating. Every
expose means seconds delay.
See also bug 605567
The khtml engine will not render an png image that exceeds 16,300px. The launchpad sprite is greater than 20,000px. No browser promises to support an image that large. Though this issue currently affects Konqueror, it could effect other browsers because there is no mechanism to ensure the sprites are sensibly sized.
tags: | added: performance ui |
Changed in launchpad: | |
importance: | Undecided → High |
status: | New → Triaged |
summary: |
- Redrawing of Bug View page very slow in Firefox + image sprite is packed very asymmetrically and triggers poor rendering + performance in firefox |
summary: |
image sprite is packed very asymmetrically and triggers poor rendering - performance in firefox + performance in firefox3 and missing icons in firefox4 |
Changed in firefox: | |
importance: | Unknown → High |
status: | Unknown → Confirmed |
description: | updated |
tags: | added: easy |
summary: |
- image sprite is packed very asymmetrically and triggers poor rendering - performance in firefox3 and missing icons in firefox4 + image sprite is packed very asymmetrically - triggers poor rendering + performance in firefox3 and missing icons in firefox4 and konquerer |
description: | updated |
Changed in launchpad: | |
assignee: | nobody → Curtis Hovey (sinzui) |
Changed in launchpad: | |
status: | Triaged → In Progress |
tags: |
added: qa-ok removed: qa-needstesting |
Changed in launchpad: | |
status: | Fix Committed → Fix Released |
tags: | added: disclosure sharing |
Changed in launchpad: | |
assignee: | Curtis Hovey (sinzui) → nobody |
Changed in firefox: | |
status: | Confirmed → Unknown |
Changed in firefox: | |
status: | Unknown → Confirmed |
Changed in firefox: | |
status: | Confirmed → Unknown |
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13
Build Identifier: Mozilla/5.0 (X11; Linux i686; rv:2.0b10) Gecko/20100101 Firefox/4.0b10
Under Linux you cannot scroll the aforementioned URL - scrolling is extremely jerky while Firefox consumes 100% of CPU.
Reproducible: Always
Steps to Reproduce:
Visit the given URL.
Actual Results:
Terribly slow and jerky scrolling.
Expected Results:
Smooth scrolling.
This problem exists both in Firefox 3.6.13 and 4.0beta10 with clean (new) profiles.
Opera 11 and Google Chrome 8 don't exhibit this problem.